Chosen Solution
Just received a 2nd hand 2015 Macbook Pro 11,5. It’s from a reputable dealer with many shops and good guarantee service - wouldn’t have bought in absence of that. I quickly and carefully opened the case to have a peek and check all is OK. The system is working fine on a trivial, initial power on & boot test. What I see on the magsafe connector is as pictured (click to see detail of deposits on connector board):
I have not detected any other issues yet except for a loose small object rattling in the upper right case (possibly a lost case screw). Questions: (1) What has likely happened to the magsafe board? (2) Will this impact reliability? (3) Will replacing the magsafe board achieve anything? (I see it’s available for $40) Thank you!
That appears to be liquid damage corrosion. I’d send a copy of this photo to your supplier if they didn’t inform you. It also needs to be replaced and the bottom of the logic board inspected for further damage. Either that or return it.
